Blends of vinyl chloride polymers with



BLENDS OF VINYL CHLOREDE PQLYMERS WITH ETHYL ENE/VINYLENE QARBONATE CGYQLY- NIERS Ival 0. Salyer and lames A. Herbig, Dayton, @hio, as-

signors to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware N Drawing. Application December 11, 39.53, i Elcrial No. 397,791

9 Claims. (Cl. 26i -45) This invention relates to improved vinyl chloride polymer materials. In one aspect the invention pertains to polyvinyl chloride of improved processability.

Vinyl chloride polymers, especially homopolymers of vinyl chloride and copolymers of vinyl chloride with not more than to weight per cent of other copolymerizablemonomers, constitute one of the most important classes of vinyl resins. Because of their inertness, nonfiammabality, and in general good physical properties, vinyl chloride polymers find many uses. vinyl chloride articles, such as sheets, tubes, rods, and the like can be made, or by addition of considerable quantity of plasticizer polyvinyl chloride is made flexible and rubbery permitting the production of garden hose, film, and the like.

Unplasticized polyvinyl chloride has very poor-processing characteristics. When milled on rolls, the sheet is notmaintained but rather is subject to severe tearing. his very difiicult to injection mold polyvinyl choride successfully because of its flow characteristics and the fact that molding temperatures are necessarily so'high as to cause significant decomposition of the polymer. It would be desirable to provide polyvinyl chloride of improved fiowability and processing characteristics without a concomitant severe decrease in heat distortion temperature, thus permitting the production of rigid polyvinyl chloride products with greater facility.

In accordance with the present invention, blends are provided'of vinyl chloride polymers with ethylene/vinyleue carbonate copolymers. Copolymers of ethylene With vinylene carbonate are new materials, and are-described in. detail in the copending application of Earl W. Glueseukamp and John'D. Calfee, Serial No. 355,859, filed May 18,1953, the contents of which application are incorporatedherein by reference. A blend of polyvinyl chloride with Jan ethylene/vinylene carbonate copolymer is much more processable than the polyvinyl chloride alone, yet the softening point or heat distortion point of the blend isnot'nearly so low as a blend of the polyvinyl chloride with the same amountof the usual low molecular weight liquid plasticizers. While polyethylene is hardly att'all compatible with polyvinyl chloride, ethylene/vinylene carbonate copolymer, although resembling polyethylene in many ways, is much more compatible-with polyvinyl chloride.

Theterms polyvinyl chloride, 'vinyl chloride polymer,.zand polymer of vinyl chloride, as used herein are intended to include homopolymers of vinyl chloride, i. e., polymers prepared by subjecting to polymerization a monomeric material consisting of vinyl chloride as the sole polymerizable constituent, and copolymers of vinyl chloride with other .ethylenically unsaturated monomers copolymerizable therewith. While :theinvention can be appliedto copolymers'with vinyl chloride containinga major proportion, i..e., over weight-per cent, vinyl chloride, it -is,most-,useul:as applied to polymersof vinyl chloride prepared from monomers containing from 100 zto '95 weight per cent vinyl chloride and '0 to '5 weight'per cent oi.-a comonomer. inasmuch as the polymerization art iszwell developed with respect to :materialswhich-are copolymerizablewith vinyl chlorideyit is not deemed necessary to provide. here -;a long list :of comonomers. Merely Rigid polyby wayof example can be mentioned vinyl acetate, vinylidene chloride, acrylonitrile, methyl vinyl ether, methyl methacrylate, styrene. See U. S. Patent No. 2,624,724, column 6, lines 19-56, for other examples of suitable comonomers. Of course, polymers made from vinyl chloride and two or more comonomers are also applicable. in any event, the p lymer employed should have a high molecular weight suitable for the use intended, i. e suitable fora usefulfilm, fiber, filament, or otherstructure.

The term blend" is used herein in a broad sense to include both mechanical blends of preformed vinyl chipride polymers with preformed ethylene/vinylene carbonate copolymers, and blends prepared by polymerizing monomeric vinyl chloride in the presence of preformed ethylene/vinylene carbonate copolymers. Thus, preformed vinyl chloride polymer and preformed ethylene/vinylene carbonate copolymer can be brought together into intimate admixture by any su'table mechanical means, such as by milling on cold or heated mill rolls, mixing in a Banbury mixer, or mixing emulsions, suspensions, or dispersions of the two polymers and coagulating same. On the other hand, anethylene/vinylene carbonatecopolymer can be incorporated in monomeric vinyl chloride and the resulting material subjected to polymerization. For best results such polymerization should be carried to a high conversion, suchas greater than per cent conversion to high ,rnoleeular weight vinyl chloride polymer. In preparing such apolymeri:zation blend, the ethylene/vinylene carbonate copolymer should be thoroughly and intimately dispersed in the monomeric material prior to polymerization. It is believed highly probable that in the practice of the embodiments of this invention involving polymerization of vinyl chloride in the presence of preformed ethylenesvinyle'ne carbonate copolymers, a certain amount of ,inter'polymerization occurs between vinyl chloride and any ene/vinylene carbonate copolymer molecules, with resultant formation of What can be calleda graftpplyrner, although it is by no means certain and is even'dgubtful that all molecules of ethylene/vinylene carbonate co.- polymer become united with one or more vi n l chloride monomer units. However, the invention is not to be limited by any theory of particular reaction mechanism. Homopolymer or copolymer of vinyl chloride, as described herein, can be any of the known vinyl c hloride polymerization techniques from monomeric ma rial comprising vin l chloride, either vwith o r withput ethylene/vinylene carbonate copolymer present. Qne of the most common of said techniques :is mass polymerization wherein the only material present in reaction mixture is plus any catalyst and any modifier that may .be used to aiiect the molecular weight, plus ethylene/vipylene carbonate copolymer if it is to be incorporated during the polymerization, and no added solvent or otherreaction medium is present. Suitable catalysts are those that promote free radicals, e. g., peroxy and az o catalysts By Way of example are benzoyl peroxide, diacetyl per oxide, dimethylphenylhydroperoxymethane, a'Qaz'bjis isobutyronitrile. Solvent polymerization is similar mass polymerization, except that a solvent tor monomer and/ or polymer is also present during the poly merization. Use of a solvent results in alowfer melee lar weight polymer. The polymerization of vinyl chi ride, with or without comonomers, can also be efieete advantageously by suspension or emulsion technique Both of these techniques involve he use of a nonrsolye. for the monomer and polymen but in the suspensit technique the particles of monomer and ultimately of tJ polymer are comparatively large, while in-theem rlsit procedure the particles are quite small ,fdlldfillf product is-astable latex. A suitable method for effecti the suspension polymerization of vinyl chloride is to employ water and a small amount of an added suspending agent, such as a vinyl acetate-maleic anhydride copolymer C. ded with vinyl chloride polymers in present invention are copolymers of ene carbonate. Properties of vinylample be from 40 The materials blen e practice of the ethylene with vinyl ene carbonate and scribed by Newman preparing vinyl carbonate is thylene carbonate to form monochlorote, followed by dehydrochlorination of by reaction with an amine, resulting in vinylene A suitable method of chlorination of e ethylene carbona the latter The invention encompasses blends of vinyl chloride polymers with ethylene merization reaction. Thus, vinyl chloride, vinyl acetate, vinyl fluoride, propylene, styrene, acrylonitn'le, and other unsaturated o nge of 0.001 to 0.5 per ers. The ethylene/vinylolymerization can be effected in the the comonom ene carbonate cop tion can also be eifected under the mfiuence of ionizing radiation of polymerizing intensity, such as gamma rays may he 1 Weight Per cent or less, and at the other extreme provided by cobalt60 or other radioactive substances, the use of polymers of vinylene carbonate containing the using the general Procedures described and claimed smallest significant quantity of ethylene, which may be the copehdmg aPPhcahoh of wluiam H Yahko and 1 Weight per cent or less, and all proportions between John D. Calfee, Serial No. 318,098, filed October 31 those extremes. However, of particular interest are ethyl- 1952- copolymers of ethylene and nylene carbonate ene/vinylene carbonate copolymers containing a ma or employed in accordance wlth the Present ihvehhon are proportion by weight of ethylene and a mmor propel-hon inclusive of modified polymeric materials known as by weight of vinylene carbonate combined in the copolyfelolhers, obtalhed by carrying out the copolymenzanon men-e materiah copolymer eomposmons Wlthm the in the presence of materials which are non-polymenzable range of ethylene/vinylene carbonate weight proportions under the conditions employed but Whlch combme with of 99:1 to 7030 are ordinarily most useful in the prac- 50 a plurality of units 9 the o om r e a. carbon tetrahee of the invention It is often preferred to prepare chloride, organic acids, esters, mercaptans, alcohols, etc. eopolymers by polymerization of monomeric materiel Addit onal details directed to the preparation of ethylcomprising ethylene and vinylene carbonate containing a ene/nylene carbonate copolymers which can be used sufiiciently high proportion of ethylene to produce a polyh the Pliesent lhvehhoha i he found m the ahovelheh zthylene-l1ke material, 1 e a high molecular Weight norhoned copehdmg apphcahoh of Earl Gluescnkamp mally solid polymer having the general properties of polyand John D. Calfee, Serial No. 355,859, filed May 18, -thylene per se, 1 e., polyethylene prepared from mononene matenal eons-snug f ethylene Vinylene carbonate units in the ethylene/vinylene car- Any suitable combination of polymerization conditions ohate COPolymers are j t t hydrolysis, whereby esuhmg m the fm-mahon of a eopolymer from a mono 0 part or all of sa1d units are converted to units of the folleric material comprising ethylene and vinylene carbonowmg type the Polymer:

te can be employed. However, in preferred embodig tents a monomeric material comprising ethylene and 0 o nylene carbonate 1s SllbjfiCtBd to copolymerization at H H gh pressures, preferably at least 5000 pounds per square The present invention includes blends of vinyl chloride ch Pressures of at least 15,000 pounds per square polymers with ethylene/vinylene carbonate copolymers :h are more preferably employed, resulting in a product that have undergone hydrolysis, and even that subsequent ving high self-compatibility (homogeneity) Often to hydrolysis have been SUbJECtEd to further treatment timum results are obtained at pressures within the range F to react other materials with part or all of the hydroxy 20,090 to 40000 pounds per square inch There IS parts vinyl chloride polymer with ,m .5. to .15 parts ethylene/vinylene carbonate '.c.qp0l ymet. Such blends can also includezif desired additional materi ls such as plasticizers, e- -B=,..dicctyl phthal e, dioctyl adipate, 'tricresyl phosphate, dioctyhsebacate, ther mal stabilizers, fillers, dyes,pigments,tother polymers,.and the like. Those skilled in the art, having had the benefit ofthe present disclosure, will be able .tochoose-bysimple tests suitable proportions ofa particular .vinyl chloride polymerand ,a particular ethylene/vinylene carbonate copolymer to ive a blendhaving characteristics desired for a particularuse.

While the compositions of the present invention :find particular use in makingrigid or-semi-rigid-polyyinyl chloridearticles, suflicient plasticizer canbeincluded to permit the production of flexible articles. Rigid sheets or structures can be compression molded, or usually with less advantage can be injection molded. Films, filaments, and the slikecan {be cast or spunfrom solution by wetspinning or dry spinning procedureswell known in the art.

The following examples provide details of certain preferredembodimentsof-theinvention. The data are tobe taken as exemplaW, and the invention in its broadest aspects is. notlimited to the particular conditions, proportions, and materials set forth therein.

.Example 1 A commercial polyvinyl chloride-resin was subjected to testing as indicated below.

This polyvinyl chloride when subjected to conventional mill-rolling undergoes tearing and shredding to a severe degree.

The following physical properties are characteristic of this polyvinyl chloride, as determined on specimens compression-molded at 165 C.

Tensile strength at failure, p. s. i 9650 Tensile elongation at failure, percent 4.5 Flexural strength, p. s. i 14,400 Flexural deflection, in 0.80 Clash-Berg data:

Tr C.) 73 T2000 C.) 91 Stifiiex range C.) 18

Ninety parts of polyvinyl chloride as described above was intimately blended with parts of an ethylene-vinylene carbonate copolymer. vinylene carbonate copolymer is described in detail in Example 2 below. On subjecting the blend of polyvinyl chloride with ethylene-vinylene carbonate copolymer to milling in the same manner to which the polyvinyl chloride alone had been subjected, it was found that the blend milled smoothly in a continuous sheet, with no tearing or shredding. Further, the improved flow characteristics of the blend make it more amenable to injection molding than the polyvinyl chloride alone. However, addition of some plasticizer is desirable in order to permit injection molding without sign of degradation.

The following physical properties were determined on compression-molded samples of the polyvinyl chlorideethylene-vinylene carbonate blend.

Addition of the ethylene-vinylene carbonate copolymer to the polyvinyl chloride appreciably lowered the tensile strength, slightly increased the tensile elongation, and did not greatly affect the flexural properties. However, use of the ethylene-vinylene carbonate copolymer in admixture with polyvinyl chloride permitted milling without difiiculties, and very markedly improved the flow char- Preparation of the ethylene acte iistics of immaterial. Th decreasesinihs ilirfila hts alue is actually w hin. .thezl mitszcf the measurement, and i to be contrasted withrcsults elatainedzwhen usin thesame mount o l w :mqle lia we ght plasticizer, which lowers the T: value .by ;3 pr4 ,Ifor-eaqh .3 per cent added-plasticizer. Thus, the blend;ef -,polyvinyl chloride .with ethylene-vinylene carbonate copolymer can still be used to produce rigid polyvinyl .chlqride articles, such as sheets, rodsgand the like.

A similar blend ch10 percentpolyethylene:in pqhflvinyl chloride gives a cheesy product of extremelyrpoor properie The I pr nt blend of ethylene-vinylene carbonate copolymer withpolyvinyl chloride is 1 1011 {more ,compatible. The blend i translucent, utais st es ed beyond the yield point the area under stress turnsWhih}. 21. creas ed concentrations ofihe copolymerresultgingreater opacity. a

Data givenin the preceding tables were detrm in,ed by the following test procedures:

Clash-Berg modulus characteristics:

A. Brittle temperature "(T-s) C. B. Rubber temperature-(Tz00 C. :C. Stifilex range (Tzono-Tr), C.

This test isa measureof thestifinessofaplasticspecir men as a function oftemperaturqmeasumdhyClash-and erg. Indu tri l and Engin ering -Ch mistril, ,3 12.18 (1942). The brittle temperature (T!) is the temperature at which the stiffness modulus is 135,000 p. s. i. The rubber temperature (T2000) is the temperature at which the stiffness modulus is 2000 p. s. i.

Tensile properties:

Strength to break, p. s. i. Elongation to break, percent.

These tests are determined by the standard tests ASTM D 6384GT, D 412-41.

Flexural properties:

Strength, p. s. i. Deflection, in.

These tests are determined by the standard test method ASTM D 79045 T.

Example 2 The ethylene-vinylene carbonate copolymeremployed in the tests described above in Example 1, was prepared as follows:

A mixture of ethylene and vinylene carbonate monomers (5 to 1 weight ratio) was polymerized at 20,000 pounds per square inch with a,e'-azodiisobutyronitrile catalyst. The bomb was charged with the monomer mixture at --78 C. and while the mixture was still cold, it was pressured to 6000 pounds per square inch with water. As the temperature rose to about 80 C., the pressure reached a maximum of 22,000 pounds per square inch. Under these conditions rapid polymerization occurred (1.75 hours) and the pressure dropped to 12,000 pounds per square inch. The copolymer was formed in 25 per cent yield. It was found by direct oxygen analysis to contain 10.7 weight per cent vinylene carbonate units in the copolymer.

The ethylene-vinylene carbonate copolymer had the following properties:

Tensile strength at failure, p. s. i 2229. Tensile elongation at failure, 470. Clash-Berg data:

Tr C.) -24. T2000 C.) 32. Stifflex range C.) 106.

Density 0.9

While the invention has been described with particular reference to various preferred embodiments thereof, it willbe appreciated that'variations from the details given herein can be effected without departing from the invention in its broadest aspects.

" We claim:

1. A blend of a vinyl chloride polymer with an ethylenevinylene carbonate copolymer.

2. A blend of a vinyl chloride homopolymer with an ethylene-vinylene carbonate copolymer.

3. A blend of a vinyl chloride polymer with a normally solid polyethylene-like ethylene-vinylene carbonate copolymer containing a major proportion by weight of ethylene and a minor proportion by weight of vinylene carbonate in said copolymer.

- 4. An intimate admixture of from 99 to 70 parts by weight of a vinyl chloride polymer with from 1 to 30 parts by weight of an ethylene-vinylene carbonate copolymer containing from 1 to 30 weight per cent vinylene carbonate in said copolymer.

5. A method of improving the hot processability of polyvinyl chloride which comprises intimately admixing therewith a lesser quantity by weight of an ethylene-vinylene carbonate copolymer comprising a major proportion byweight of ethylene and a minor proportion by weight of 2c vinylene carbonate in said copolymer.

t3. A normally rigid polyvinyl chloride structure containing from 95 to 85 parts by weight of polyvinyl chloride and from 5 to 15 parts by weight of a normally solid poly ethylene-like ethylene-vinylene carbonate copolymer comprising from 70 to 99 weight per cent ethylene and from 30 to 1 weight percent vinylene carbonate in said dopolymer.

/ 7. A blend according to claim 1 wherein said vinyl References Cited in the file of this patent UNITED STATES PATENTS Adelson Aug. 7, 1951 FOREIGN PATENTS 985,327 France Mar. 7, 1951 1,037,565 France May 6, 1953 OTHER REFERENCES Heyes, 637, O. G. 591, August 8, 1950. 

1. A BLEND OF A VINYL CHLORIDE POLYMER WITH AN ETHYLENEVINYLENE CARBONATE COPOLYMER. 